Canine Cancer Studies Yield Human Insights

Some of the most promising insights into cancer are coming from pet dogs thanks to emerging studies exploring remarkable biological similarities between man and his best friend.

Cancer is the leading cause of death in dogs. Every year, millions of dogs develop lymphomas and malignancies of the bones, blood vessels, skin and breast. An increasing group of researchers recognize cancer-stricken canines as a natural study population, especially given owners' storied devotion to their canine companions' well-being.

Because dogs age many times more rapidly than humans and their cancers progress more quickly, canine cancer studies produce quicker results. Veterinary oncologists talk in terms of "one- to two-year survival times" for their pet patients, compared to survival times of five to 10 years that oncologists discuss for their human patients, said Dr. Melissa Paoloni, a veterinary oncologist with the National Cancer Institute's Center for Cancer Research in Bethesda, Md.

A consortium of 20 veterinary centers created by the NCI and overseen by Paoloni aims to speed the development of better therapies and new strategies for treating and preventing human cancers. At the same time, some institutions, such as the M.D. Anderson Cancer Center in Houston and Texas A&M in College Station, Texas, are independently teaming up on their own to share human and animal findings.

One beneficiary of that collaboration has been Rowdy, an 8-year-old Great Pyrenees dog diagnosed in August with bone cancer.

Rowdy might have undergone chemotherapy and amputation of his front leg had his owner opted for conventional therapy. But Kate Cordts of San Antonio lost another dog to the same disease and assiduously researched experimental treatments for canine osteosarcoma.

She enrolled Rowdy in a clinical trial at Texas A&M, where veterinary cancer specialists delivered experimental radiation therapy directly into his diseased leg, followed by chemotherapy.

Six months later, Rowdy is living up to his name, thanks to a regimen that not only saved the leg, but also might one day help children diagnosed with the same malignancy.

"One of the great advantages of doing clinical trials in dogs is that owners can elect to do experimental therapy instead of conventional from the very beginning," Dr. Terry Fossum, the Texas A&M veterinarian who administered Rowdy's limb-sparing, potentially life-saving treatment, told ABC News.

People, in contrast, typically undergo experimental treatments only after conventional treatments have failed.

Paoloni said the Comparative Oncology Trials Consortium has so far conducted 11 clinical trials. Its pilot study of just 31 dogs demonstrated that scientists could conduct sophisticated molecular profiling of tumors and, within five days, use it to create a personalized treatment plan based on an individual dog's profile, Paoloni told ABCNews.com. The study stands at the cutting edge of personalized medicine, she said.

Investigators currently are designing three early-stage trials of this approach for larger numbers of dogs with melanoma, osteosarcoma and angiosarcoma. She expects those to begin late this year or early in 2013.

Since the identification of the dog genome in 2005, researchers have been identifying genetic changes associated with dog cancers and comparing them to changes "in corresponding human cancers" to figure out where there is overlap, said Dr. Matthew Breen, an associate professor of genomics at NC State University School of Veterinary Medicine in Raleigh, N.C., one of the consortium schools. By being able to "tease out the major genes associated with cancers in other species and then assess the role of these genes," scientists have found changes in canine lymphoma that can predict how well that dog will respond to standard chemotherapy, a finding that could potentially benefit as many as 300,000 dogs diagnosed each year.

By seeing if the same changes in human lymphoma can predict treatment success, "this translation from dog to human" might improve doctors' ability to predict the responses of "up to 70,000 Americans" diagnosed with lymphoma each year, he said.

Assuring these programs can thrive depends upon making pet owners aware of clinical trials. Texas A&M's Fossum, who helped establish the Texas Veterinary Cancer Registry, told ABC News she hopes to make the registry a national resource linking more pet owners with clinical trials.

In the meantime, word is slowly getting around that clinical trials can be a win-win for pets and people.

Canine clinical trials have the potential to accelerate progress in the fight against cancer, helping "patients with and without fur," Paoloni told ABCNews.com Tuesday. "All of our interests are geared to learning something from the dog that's applied to human patients."